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Printing 3D Organs

Frank Graff looks at the future of regenerative medicine with 3D printing using human cells in a growth medium. He talks with Dr. Anthony Atala about the printer's potential to replace damaged organs.

WINSTON-SALEM — The lab at The Wake Forest Institute for Regenerative Medicine looks pretty much like any other lab.

Looking around, you'll see tables covered with lab equipment, beakers, petri dishes and microscopes. You can hear the constant hum of electrical fans cooling the equipment—all under the bluish glow of fluorescent lights.

And in the back of one of the rooms there’s a machine that looks pretty much like the standard 3D printer. You’ll find lots of ink reservoirs and nozzles, a computer to program what’s printed and an automated system that slowly builds a model, layer upon layer. However, this device is anything but your standard printer.

“So the strategy that we’re working on is to take a very small piece of tissue from a patient, less than half the size of a postage stamp, and then we then expand the cells outside the body,” explains Anthony Atala, Ph.D. and director of The Wake Forest Institute for Regenerative Medicine. “We then place the cells in cartridges, just like an ink jet cartridge, but instead of ink we use cells, and we then print the structure one layer at a time.”

Atala adds that as the machine prints the cells, it is also printing the structure that holds them.

The device that is doing all of this amazing work is the integrated tissue and organ printing system. What it prints is alive.

What you get in the final product are tens of millions of living cells, suspended in a gel. There’s also a precise latticework of microchannels, 200 microns wide, imprinted into the system. Those microchannels are intended to allow blood vessels and nerves to generate after implementation, and the vessels then allow blood and nutrients to flow through the tissue.

The printed organ, made from the patient’s own cells, is designed to be surgically implanted back into the patient. Because the system is using the patient’s own cells to create the tissues and organs, the body recognizes them and adapts them as their own.

“It’s a very elegant system because once the body recognizes the cells, blood vessels and nerves will actually grow into these tissues and they will become functional inside the body,” says Atala.

The framework is a 3D model, created from an X-ray of the patient’s actual organ. And because each organ has specialized cells, the tissue sample is taken from the specific organ to be printed and a protocol is designed to expand the cells.

“With this technology, you are taking the patient’s own cells and combining them with a glue-like substance,” explains Atala. He says that once the tissue or organ is made, it is placed into a warming device for a few days before being implanted into the patient.

“But when this gets implanted in a patient, the cells remain but the glue goes away and it gets replaced by the patient’s own glue,” adds Atala. “So six months later you’re left only with the patient’s own tissues and organ.”

So far, the research team has implanted flat structures such as skin, hollow tubular structures like blood vessels and windpipes, and hollow non-tubular organs such as a bladder and a stomach.

But those tissues and organs were hand-made in the lab and the customized scaffolds were coated by hand with the patient’s cells.

It turns out that printer in the back of the lab is the future of regenerative medicine. The goal is to utilize 3D printers that can scale up the process so tissues and organs don’t have to be tailor-made.

And the future is promising. The new printing system, with its breakthrough technology of microchannels, has created 3D printed muscle and bone that have been successfully implanted in animals. Those microchannels allowed blood vessels and nerves to generate after implementation. The research team expects to test the 3D printed organs on humans within the next two years.

“For us, of course, there are all these challenges everyday: How will you solve this problem? How do you solve this other problem?,” explains Atala, who takes successes and setbacks all in stride. “There are all these challenges that you have to face and you have to solve, so there is no big eureka moment. It’s really a lot of hard work that goes into making sure these technologies really do work.”